Iíve got a couple of New Old Stock vintage JBL D140F 15Ē Bass speakers lying about - and for a long time Iíve wanted to build (or maybe have built) a replica Vintage Cab to put them in. I'm thinking around a 70ís style 2 x 15 ď cab as would have been around and popular when these classic speakers were in production.

I wondered if anyone on Basschat had any ideas about what would be a good, or indeed ďTheĒ classic bass speaker enclosure design, that I should aim to recreate ? . .

Iíve done a little googling on this and, for example, the old 70s Sun 2 x 15Ē bass cab seems to command some respect . . and so I thought Iíd try and look in to getting the info to copy one of those ? . . but unfortunately I cant find any info on exactly what that cabs design was like (ie, dimensions, port design, internal stiffening etc) . . . . so at the moment the project is at a sort of impasse due to lack of information on the design/construction of a chosen old 70ís classic cab design ?

Anyway, any thoughts gladly received and/or any links to advice on technical/design information on any classic 70ís bass cabs that would be worth investigating for this project. Indeed any input very much appreciated.

Or, any info on any cab builders around who might be able to knowledgably create a good authentic reproduction/replica 70ís cab for me ? (I havenít dismissed the option of getting the cab made professionally if I could find someone who would do a really good authentic job of it ?)

I used to have an old JBL brochure which specced cabs and chassis in great depth..but it is long gone now.

Mostly though, IIRC, it concentrated on reflex bins like the 4550

I still have the speakers looking for a new hom..and I think both are D140 or K series.
I am not sure if the Fender cabs used D140's.... but JBL should surely have some stuff on the i-net for this sort of thing..
being as they were pretty much the benchmark chassis for so long..???

You'd design a cab for D140s the same way as you would for any other driver, using a program like WinISD Alpha Pro and the driver T/S specs. Specs for the D140 are not available, unless you measure them yourself, but those for the D130 will be close enough, as it was almost identical. Copying a vintage cab wouldn't get you anywhere near as good as a result, as those cabs were all 'seat of the pants' designs that worked far from as well as possible. Take the Sunn, for instance. That is not a rear-loaded folded horn. The designer, Conrad Sundholm, didn't even know what a rear-loaded folded horn was, let alone how to design one. He'd just seen the term and used it to describe the 200S, despite not having a clue what it meant.

The laws of physics aren't swayed by opinion.
www.billfitzmaurice.com
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He is looking for a 70s design, not looking to design a new cab. A 70s speaker in a 70s design cab that would have had that speaker in will give you a 70s sound, which I would kind of hope is his design goal here. Suggesting he make a new design, with knowledge he doesn't have applied to specifications that aren't available is astoundingly unhelpful.

He is looking for a 70s design, not looking to design a new cab. A 70s speaker in a 70s design cab that would have had that speaker in will give you a 70s sound, which I would kind of hope is his design goal here. Suggesting he make a new design, with knowledge he doesn't have applied to specifications that aren't available is astoundingly unhelpful.

If advising someone to use an archaic intrinsically flawed design that doesn't bring out the best that the drivers used can offer is helpful I'll always choose to be unhelpful, astoundingly or otherwise. But I won't deny the value of those 60s cabs, having to suffer their inadequacies was the impetus for my learning how to design better cabs than I could buy.

Edited by Bill Fitzmaurice, 18 June 2011 - 03:47 PM.

The laws of physics aren't swayed by opinion.
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Must say, I haven’t got access to, or the knowledge of, WinISD Alpha Pro so not sure I'm likely to be able to employ anything like a computer program to any advantage, but I do take the point that it could produce a more optomised cab design/environment for the speakers . . . having said that I wouldn't know what effect that would have on the sound/tone/character of the cab ? . . I guess we all sort of know that basic sound that 2 x 15"cabs tend to have . . . and I sort of like that old vintage sound . . . and that’s definitely what I'm after here ?

Obviously I'd like to create a cab that presents a good environment for those drivers to sit in . . one that would let them sound their best and operate properly ? . . I hadn't realised that the 70's cabs were developed with so little technical input . . sounds like it was more luck than judgement if they sounded good ? . . .

I do like the picture posted up by Mr Foxen . . . thats the sort of thing I had in mind I think ?

I’d definitely like to get a 70’s sound from this cab, thats the whole point of the exercise, but if a seventy’s design can be tweaked a bit to allow the speakers to perform even better without loosing the 70’s character then that would be worth doing I think ? . . .

Must say, I havenít got access to, or the knowledge of, WinISD Alpha Pro so not sure I'm likely to be able to employ anything like a computer program to any advantage, but I do take the point that it could produce a more optomised cab design for the speakers . . . having said that I wouldn't know what effect that would have on the sound/tone/character of the cab ? . . I guess we all sort of know that basic sound that 2 x 15"cabs tend to have . . . and I sort of like that old vintage sound. . . and thatís definitely what I'm after here ?

Obviously I'd like to create a cab that presents a good environment for those drivers to sit in . . one that would let them sound their best and operate properly ? . . I hadn't realised that the 70's cabs were developed with so little technical input . . sounds like it was more luck than judgement if they sounded good ? . . .

I do like the picture posted up by Mr Foxen . . . thats the sort of thing I had in mind I think ?

Not sure where to go next now ! . . .

Further comments much appreciated !

Most of the midrange colouration that you hear is the speakers, that will be the same between cabs, aside from some stuff fro the box not being lined and stuff. I don't actually know if the old cabs were lined or not, it is kind of important, guitar cabs are pretty much never lined, and they are all about speaker colouration. WinISD deals with the stuff below 200hz, in the bass sort of area, old cabs tend toward a midbass hump, remove that and you've removed an important part of the sound, you can design it in with WinISD if you know how, but it defaults to flat, rather than humped. Mostly, the coloured one I posted is awesomely large and heavy.

I wouldn't know what effect that would have on the sound/tone/character of the cab ? . .

Not that much. They did manage to get a pretty good result with some of those old cabs. But it was all trial and error, and with a software designed cab there's no trial, and more important, no error. You can get the best possible result from the drivers used with the smallest possible cab. For example, the JBL 4625 electric bass cab loaded the E140 into a 127 liter (net) 40kG cab. It embodied the best of what designers knew circa 1980. It's twice the size and weight required.

The laws of physics aren't swayed by opinion.
www.billfitzmaurice.com
www.billfitzmaurice.info/forum

Good evening, Nostromo...
A simple solution perhaps would be to obtain a Fender Bassman 2 x 15 cab..? They came with (optional...) K140s, and, imho, sound top. I have such a cab, but, for lack of funds to equip with K140s, I've installed Beyma equivalents. If I get the opportunity, I shan't hesitate to swap out for the real JBLs (anyone got a pair spare, affordable..?).
There's certainly not much scientific hocus pocus in the Fender 'design' (it's basically just a biggish box...), but it fits the bill for me as far as '60s/'70s sound goes (Hofner Verithin bass, Hiwatt DR203 amp; can't get much more vintage than that, but then, I'm old...)
Hope this helps.

Good evening, Nostromo...
A simple solution perhaps would be to obtain a Fender Bassman 2 x 15 cab..? They came with (optional...) K140s, and, imho, sound top. I have such a cab, but, for lack of funds to equip with K140s, I've installed Beyma equivalents. If I get the opportunity, I shan't hesitate to swap out for the real JBLs (anyone got a pair spare, affordable..?).
There's certainly not much scientific hocus pocus in the Fender 'design' (it's basically just a biggish box...), but it fits the bill for me as far as '60s/'70s sound goes (Hofner Verithin bass, Hiwatt DR203 amp; can't get much more vintage than that, but then, I'm old...)
Hope this helps.

I have a K140 and a D140... both may need a recone. One certainly would.

There is an old Acoustic 2x15 in the for sale section at the minute. If it's the sort of thing you're looking to do, I can take pics/measurements of mine for you. I'm about to put the original speakers back in mine (I replaced them with Eminence betas to increase the power handling when using my Ashdown 600w head) So it will be in bits sometime soon and would be no problem to have a quick measure up.

The Fender Dual Showman used these speakers so I guess you could look to one of those for the design.

The one thing I remember from owning one was that it didn't have a "vintage" sound. Depends on you definition of "vintage" I suppose, but my Dual Showman had a very clean and clear sound. Almost the opposite of Ampeg and any of the British amps that were around at the time.

There is an old Acoustic 2x15 in the for sale section at the minute. If it's the sort of thing you're looking to do, I can take pics/measurements of mine for you. I'm about to put the original speakers back in mine (I replaced them with Eminence betas to increase the power handling when using my Ashdown 600w head) So it will be in bits sometime soon and would be no problem to have a quick measure up.

Must say, I havenít got access to, or the knowledge of, WinISD Alpha Pro so not sure I'm likely to be able to employ anything like a computer program to any advantage, but I do take the point that it could produce a more optomised cab design/environment for the speakers . . . having said that I wouldn't know what effect that would have on the sound/tone/character of the cab ? . . I guess we all sort of know that basic sound that 2 x 15"cabs tend to have . . . and I sort of like that old vintage sound . . . and thatís definitely what I'm after here ?

Obviously I'd like to create a cab that presents a good environment for those drivers to sit in . . one that would let them sound their best and operate properly ? . . I hadn't realised that the 70's cabs were developed with so little technical input . . sounds like it was more luck than judgement if they sounded good ? . . .

I do like the picture posted up by Mr Foxen . . . thats the sort of thing I had in mind I think ?

Iíd definitely like to get a 70ís sound from this cab, thats the whole point of the exercise, but if a seventyís design can be tweaked a bit to allow the speakers to perform even better without loosing the 70ís character then that would be worth doing I think ? . . .

Not sure where to go next now ! . . .

Further comments much appreciated !

WinISD is a free program which google will find straight away. You probably need to know a bit about speakers to drive it though. AJ systems offer a simpler though less flexible box caculator which will offer optimum box sizes.

The basic theories of box design were first published in the early 70's and many designers didn't pick them up until later so almost no cabs sold then were designed using the Thiele/Small models. In addition materials technology was developing so drivers got better. At the beginning of the decade most amps were valve amps with a very high price per watt. Speakers were usually general purpose designs with paper voice coils and low power handling. Magnets were small and often lost a lot of there power over time. There were very few horn tweeters around and these were expensive and unreliable. Most speakers tried to cover the whole audio range and tended to have thin flexible cones often with a second 'whizzer cone ' in the middle of the main cone to boost the higher frequencies. To get the most out of the low powered amps the voice coils tended to be short to boost efficiency and suspensions were often soft to lower the resonant frequencies.

All this meant that most speakers were in boxes that were often too small and that the designs were often under damped meaning that you got a nice warm bass frequency hump at the expense of deep bass. Distortion set in early because of the lack of excursion and the only way of getting deep bass was using big speakers (2x15) or lots of them (8x10). By the end of the 70's glass fibre coil formers were creeping in and large ceramic magnets were common and designers were starting to use maths to design cabs though remember computers still used punched cards in the early 70's and pocket calculators were just being introduced. I was still using a slide rule and mechanical caculators at University.

Bill is right, you'll get a better sound and more quickly without the error part of trial and error if you use a computer modeller. the seventies procedure was to listen to a lot of speakers so you knew the basic sound of each driver and then to keep building cabs untill you'd home in on the sound you wanted. Sometimes you had a lucky accident. Your best bet is to copy an earlier design where someone has done all this for you. Most of the 'character' apart from deep bass will come from the drivers.

All this meant that most speakers were in boxes that were often too small and that the designs were often under damped meaning that you got a nice warm bass frequency hump at the expense of deep bass.

True for the most part, because most drivers of that period out of the Jensen/Celestion mold had high Q values. That made them best suited to large sealed cabs. However, JBLs were at the opposite end of the scale, with very low Q values. That made them best when used in small vented cabs. Yet you would find both JBLs and Jensens/Celestions used in the same cabs. Fender used the D130F and D140F in a large volume per driver vented Showman cab and a small volume per driver sealed Dual Showman cab. Why? Because they didn't know any better. What science that did exist in the field of loudspeaker cabinet design in that era was very much restricted to the theatrical and hi-fidelity genres, being totally unknown in the musical instrument industry. That's why searching out a cab of that period, or a design for same, is of highly dubious value.

The laws of physics aren't swayed by opinion.
www.billfitzmaurice.com
www.billfitzmaurice.info/forum

I have two nice (well I think so ?) vintage JBL D140 speakers that really need to be used . . . . . . . whats the point otherwise ? ?

Plus . . a moderate budget to either build a cab or ask a cabinet maker/carpenter to run one off . . . and one way or another to glue / fix it all together . . . . I can do that . . . but would equally be interested in involving a pro builder that knew a lot more than me about the whole cab design thing ?

And, then, I've got a further budget to have the cab covered in a nice tolex and grill cloth outfit . . . so that it doesn't look like a completely home made affair ! . . . I just want it to sound like a good old vintage Seventies 2 x 15 ?

And I've got a couple of nice vintage valve amps to drive it with . . . . so it needs to have an overall vintage vibe . . . .

And I've even got a blues/70's rock band . . . so I can go out and gig it ! ! !

...One of my best bass mates just sent me a text saying...sell the D140's...order a barefaced Dubster...

I wouldn't want to bust up any long-standing friendships, but I don't think I'd class a Dubster as 'Old school vintage', even less so when compared to D140s. There are many guitarists using these 15" speakers, they are almost classable as 'full-range' (certainly not limited to only sub-bass...). No disrespect to Barefaced, of course, but it's not at all comparable.
The D140 (and K140...) are in a different league, and, to me at least, define 'vintage' bass. Can't be done with more modern (more efficient, lighter, more powerful...) cabs, which are excellent in their own right. They're just not 'vintage' sounding. A Porsche Boxster is (probably...) a fine car, but it's not the same sensation as an MG TF, or Austin-Healey 3000.
I see from your sig. that you are already equiped with (excellent...) modern cabs. Try your D140's in a chipboard box, Bassman sized; if you really don't like the result you'll have spent very little; if you like it, upgrade the woodwork according to budget and taste.
Just my tuppence worth...
(I'd be careful just the same about 'diming' the DR405 into such a cab; the chipboard will not resist for long..!)

Hi there , if the old amps / speakers were so terrible how come all the major amp brands offer ''modelling '' amps to try and re-create those sounds we had in the seventies .
I am on my 6th cabinet and my approach to building would probably give the computor boys hysterics.
1) snap up a cheap speaker on e-bay
2) Rummage around wood-shed for suitable wood , the more I can re-cycle , the better .
3) Build the box ,I'm probably a better woodworker than sound engineer .

I have built cabinets out of 100year old pine ( rescued from a Victorian house doorframe ) Fender used pine in his early cabinets , Used 80 year old Mahogany from an old fireplace ( Brian May built his guitar from a mahogany fireplace )
Used Meranti from a Salvation army hall Stairposts , made front panels of laminated American Oak with mahogany stingers (just like the old Hobie Surfboards ) , each cab sounds different , but they are unique . I gig them and receive nothing but good feed-back and requests from other players to build them a cab .
Perhaps in this over -computorised age , we need a bit more of '' seat of pants '' engineering
One thing a computor program cannot give you is the pride you have when you plug in your cab that you've made it with your own hands .
Rant over - I think I'll crawl back into Woodshed now .
Martin.

Although I'm a big fan of using technology to help you design a better product, that doesn't mean that gut feeling, intuition, lateral thinking and inspired creativity (much as used when writing songs) aren't all critical factors in the design process. I've never once done what a computer program has 'told' me to do. You could say that some of these tools are like knowing basic music theory whilst others are like having the tools to compose and arrange an entire operatic score. Even with those tools your brain has to do the bulk of the work. But that doesn't mean you can't take the punk approach to cab building if you prefer cutting and glueing wood!

I believe those JBLs aren't vastly dissimilar to the speaker we use in the Compact (though with lower power handling). That's a world of tone away from the Dubster though!

One of my best bass mates just sent me a text saying . . . . sell the D140's . . . .

Nooo don't sell them! Don't worry about computer design or any of that other stuff. If you want a cab that sounds like that era, build a copy of one from that era. No need to over-complicate it. Knowing you built it yourself is about 10000x more satisfying and rewarding, too

The links that Mr. Foxen gave you should get you the information that you need, those Sunn cabs are really great, even though admittedly their design is utterly nonsensical in some ways, who cares lol -- good luck and be sure to post the results in the build diary section!

Other option is to hunt out an unloaded 2x15. If you can get hands on it, should cost you very little, shipping is the pain. PM Thornybank, I know he has various things to suit, and probably the inclination to unload them if they are loaded. Spendier method is to have Matamp make you an unloaded 2x15.

I just want it to sound like a good old vintage Seventies 2 x 15 ? ... What should I do next?

Keep it simple. You want a cab that sounds like a 70's 2x15? Buy an old one or make a new one from a relevant design. Load it. Gig it. S'logical.

If you follow the super-wizzo-computerised-modern-lightweight-approximation-reinvented wheel approach, you'll always be wondering if you did the right thing. Nothing worse than that. Makes your head hurt and not in a good way.

(No, just kidding; I do things the empirical way too. Not always so proud of the results, though..!)

Hey , we have had electricity for at least 10 years now , but we just got this new fangled thing called ceefax .
I have nothing but respect for guys like Alex , whose cabinets probably sound 100 times better than mine , but the OP is interested in building his own cabinet , and most people seem to be trying to put him off or confuse the guy with computor talk . Basic woodwork skills are a must , and a well build , sealed , cabinet will look /sound alot better than something which looks as if its going to collapse .
A lot of people will follow computors blindly , ie , motorists driving straight into rivers because their SatNav tells them to keep driving straight on , so use of Brain + Hands is neccessary .
A sheet of 8' by 4' 13 ply Marine Ply will cost approx £55 and any decent builders yard /timber merchant will give you as many accurate cuts to make the basic shape of the cab , if your corners are 90 degrees , most things fall into place .
Most cab depths seem to be approx 15 inches , I suspect this has more to do with Tolex coming in 36 inch width to allow economical use of this expensive material .
Sea Sick Steve built a guitar out of a hubcap given to him by Jack White , If my approach is a bit unorthodox , I make no apologies .
Martin.

Martin, I`m with you.
You learn about this stuff by sawing wood, not entering numbers into software.
Half the time its completely wrong, but sounds fine.
Sounds like fun to me.
To the OP, agreed on the finding a sun or similar or even peavey 2x15 box and having a listen before you decide to build your own, you may just decide you found that sound.